Disallow kickstarts in /etc/cobbler
Restrict kickstart template/snippet files location to directories in /var/lib/cobbler/
Split methods that perform IO operations in kickstart template/snippet files

Motivation: improve cohesion and readability
Go to list of snippets/kickstarts when snippet/kickstart is saved

To keep behaviour consistent with other items (systems, distros, etc),
go to list of snippets/kickstarts when a snippet/kickstart is saved.
Merge pull request #966 from alanoe/alanoe/improve_kickstart_templates_handling

alanoe/improve kickstart templates handling